diff --git a/js/preload.js b/js/preload.js
index 2150ca6..aae4d57 100644
--- a/js/preload.js
+++ b/js/preload.js
@@ -1,2 +1,7 @@
-window.addEventListener('DOMContentLoaded', () => {
+const { contextBridge, ipcRenderer } = require('electron/renderer');
+
+contextBridge.exposeInMainWorld('signage', {
+	watchdog: {
+		reset: (payload) => ipcRenderer.invoke('signage:watchdog:reset', payload)
+	}
 });
\ No newline at end of file
diff --git a/js/watchdog.js b/js/watchdog.js
new file mode 100644
index 0000000..cab19c7
--- /dev/null
+++ b/js/watchdog.js
@@ -0,0 +1,87 @@
+const http = require('node:http');
+
+const WATCHDOG_CHANNEL = 'signage:watchdog:reset';
+const WATCHDOG_PATH = '/tooloop/api/v1.0/system/watchdog/reset';
+const REQUEST_TIMEOUT_MS = 5000;
+
+function isValidPayload(payload) {
+    return payload !== null &&
+        typeof payload === 'object' &&
+        !Array.isArray(payload) &&
+        Object.keys(payload).length === 1 &&
+        Object.hasOwn(payload, 'healthy') &&
+        typeof payload.healthy === 'boolean';
+}
+
+function isAuthorizedWatchdogEvent(event, mainWindow, isUrlAllowed) {
+    if (!mainWindow || mainWindow.isDestroyed() || event.sender !== mainWindow.webContents) return false;
+    if (!event.senderFrame || event.senderFrame !== event.sender.mainFrame) return false;
+    return isUrlAllowed(event.senderFrame.url);
+}
+
+function sendWatchdogReset(payload, httpClient = http, timeoutMs = REQUEST_TIMEOUT_MS) {
+    if (!isValidPayload(payload)) {
+        return Promise.reject(new TypeError('Watchdog reset payload must contain only a boolean healthy field'));
+    }
+
+    const body = JSON.stringify({ healthy: payload.healthy });
+
+    return new Promise((resolve, reject) => {
+        let settled = false;
+        let timeout;
+
+        const finish = (callback, value) => {
+            if (settled) return;
+            settled = true;
+            clearTimeout(timeout);
+            callback(value);
+        };
+
+        const request = httpClient.request({
+            hostname: 'localhost',
+            path: WATCHDOG_PATH,
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' }
+        }, (response) => {
+            response.resume();
+            const statusCode = response.statusCode;
+            if (!Number.isInteger(statusCode) || statusCode < 200 || statusCode >= 300) {
+                finish(reject, new Error(`Watchdog service returned HTTP ${statusCode ?? 'unknown'}`));
+                return;
+            }
+            finish(resolve);
+        });
+
+        request.on('error', (error) => finish(reject, error));
+        timeout = setTimeout(() => {
+            request.destroy(new Error(`Watchdog request timed out after ${timeoutMs} ms`));
+        }, timeoutMs);
+        request.end(body);
+    });
+}
+
+function registerWatchdogHandler(ipcMain, { isAuthorized, onError = () => {}, httpClient = http } = {}) {
+    ipcMain.handle(WATCHDOG_CHANNEL, async (event, payload) => {
+        try {
+            if (!isAuthorized || !isAuthorized(event)) {
+                throw new Error('Watchdog reset is not authorized for this renderer');
+            }
+            if (!isValidPayload(payload)) {
+                throw new TypeError('Watchdog reset payload must contain only a boolean healthy field');
+            }
+            await sendWatchdogReset(payload, httpClient);
+        } catch (error) {
+            onError(error);
+            throw error;
+        }
+    });
+}
+
+module.exports = {
+    WATCHDOG_CHANNEL,
+    WATCHDOG_PATH,
+    isAuthorizedWatchdogEvent,
+    isValidPayload,
+    registerWatchdogHandler,
+    sendWatchdogReset
+};
\ No newline at end of file
diff --git a/main.js b/main.js
index 0ce1e39..c4cb728 100644
--- a/main.js
+++ b/main.js
@@ -1,4 +1,4 @@
-const { app, BrowserWindow, nativeTheme, Menu, MenuItem } = require('electron/main');
+const { app, BrowserWindow, nativeTheme, Menu, MenuItem, ipcMain } = require('electron/main');
 const path = require('node:path');
 const { fileURLToPath } = require('node:url');
 const fs = require('fs');
@@ -7,6 +7,7 @@ const { default: isReachable } = require('is-reachable');
 const { setTimeout: delay } = require('node:timers/promises');
 const config = require('./js/config.js');
 const { Config } = require('./js/config.js');
+const { isAuthorizedWatchdogEvent: isWatchdogEventAuthorized, registerWatchdogHandler } = require('./js/watchdog.js');
 
 
 //------------------------------------------------------------------------------
@@ -163,30 +164,53 @@ function createMenu() {
  * @returns `true` if the url is allowed, `false` otherwise
  */
 function validateDomain(event) {
+    if (isUrlAllowed(event.url)) return true;
+    event.preventDefault();
+    log.info("Navigation to " + event.url + " prevented");
+    return false;
+}
+
+function isUrlAllowed(urlString) {
     if (config == undefined || config.data == undefined) return true;
 
-    let url = new URL(event.url);
+    let url;
+    try {
+        url = new URL(urlString);
+    } catch {
+        return false;
+    }
 
-    // allow local urls
     if (['file:', 'file'].includes(url.protocol)) return true;
 
     if ('whitelist' in config.data &&
         Array.isArray(config.data.whitelist) &&
         config.data.whitelist.length > 0 &&
         !config.data.whitelist.includes(url.hostname)) {
-        event.preventDefault();
-        log.info("Navigation to " + event.url + " prevented");
         return false;
     }
 
     return true;
 }
 
+function isAuthorizedWatchdogEvent(event) {
+    return isWatchdogEventAuthorized(event, win, isUrlAllowed);
+}
+
+function logWatchdogError(error) {
+    log.warn('Watchdog reset failed: ' + (error?.message || error));
+}
+
+function registerWatchdogBridge() {
+    registerWatchdogHandler(ipcMain, {
+        isAuthorized: isAuthorizedWatchdogEvent,
+        onError: logWatchdogError
+    });
+}
 
 /**
  * Tests if the host of the url is reachable.
  * Access is tried in a 1 second interval and the url is loaded if successfull.
- * @param {string} testurl 
+ * @param {string} testurl
  */
 async function loadUrlAsync(testurl) {
     const request = ++navigationRequest;
@@ -299,6 +323,7 @@ app.whenReady().then(() => {
     log.info('Starting Tooloop Kiosk Browser...');
     log.info('Logging to ' + log.transports.file.resolvePathFn());
 
+    registerWatchdogBridge();
     createMenu();
     createMainWindow();
 });
diff --git a/package.json b/package.json
index c83afea..5a9d421 100644
--- a/package.json
+++ b/package.json
@@ -8,6 +8,7 @@
   "version": "1.0.0",
   "main": "main.js",
   "scripts": {
+    "test": "node --test",
     "start": "electron-forge start",
     "clean": "rm -fr out",
     "package": "electron-forge package",
diff --git a/test/watchdog.test.js b/test/watchdog.test.js
new file mode 100644
index 0000000..f72591b
--- /dev/null
+++ b/test/watchdog.test.js
@@ -0,0 +1,121 @@
+const assert = require('node:assert/strict');
+const { EventEmitter } = require('node:events');
+const test = require('node:test');
+const {
+    WATCHDOG_CHANNEL,
+    WATCHDOG_PATH,
+    isAuthorizedWatchdogEvent,
+    registerWatchdogHandler,
+    sendWatchdogReset
+} = require('../js/watchdog.js');
+
+function createHttpClient({ statusCode = 204, hang = false } = {}) {
+    const calls = [];
+    const httpClient = {
+        request(options, onResponse) {
+            const request = new EventEmitter();
+            request.destroy = (error) => request.emit('error', error);
+            request.end = (body) => {
+                calls.push({ options, body });
+                if (!hang) {
+                    queueMicrotask(() => onResponse({ statusCode, resume() {} }));
+                }
+            };
+            return request;
+        }
+    };
+    return { httpClient, calls };
+}
+
+test('sends healthy true as a fixed local POST', async () => {
+    const { httpClient, calls } = createHttpClient();
+
+    await sendWatchdogReset({ healthy: true }, httpClient);
+
+    assert.deepEqual(calls, [{
+        options: {
+            hostname: 'localhost',
+            path: WATCHDOG_PATH,
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' }
+        },
+        body: '{"healthy":true}'
+    }]);
+});
+
+test('sends healthy false in the request body', async () => {
+    const { httpClient, calls } = createHttpClient();
+
+    await sendWatchdogReset({ healthy: false }, httpClient);
+
+    assert.equal(calls[0].body, '{"healthy":false}');
+});
+
+test('rejects malformed payloads without making a request', async () => {
+    const { httpClient, calls } = createHttpClient();
+
+    for (const payload of [null, [], {}, { healthy: 1 }, { healthy: true, url: 'http://example.test' }]) {
+        await assert.rejects(sendWatchdogReset(payload, httpClient), /boolean healthy field/);
+    }
+
+    assert.equal(calls.length, 0);
+});
+
+test('rejects non-success HTTP responses without parsing their body', async () => {
+    const { httpClient } = createHttpClient({ statusCode: 503 });
+
+    await assert.rejects(sendWatchdogReset({ healthy: true }, httpClient), /HTTP 503/);
+});
+
+test('rejects responses without a numeric HTTP status', async () => {
+    const { httpClient } = createHttpClient({ statusCode: null });
+
+    await assert.rejects(sendWatchdogReset({ healthy: true }, httpClient), /HTTP unknown/);
+});
+
+test('rejects requests that exceed the timeout', async () => {
+    const { httpClient } = createHttpClient({ hang: true });
+
+    await assert.rejects(sendWatchdogReset({ healthy: true }, httpClient, 5), /timed out after 5 ms/);
+});
+
+test('rejects unauthorized renderers without making a request', async () => {
+    let registeredChannel;
+    let handler;
+    const { httpClient, calls } = createHttpClient();
+    const mainFrame = { url: 'https://allowed.example/' };
+    const mainWindow = { isDestroyed: () => false, webContents: { mainFrame } };
+    const ipcMain = {
+        handle(channel, registeredHandler) {
+            registeredChannel = channel;
+            handler = registeredHandler;
+        }
+    };
+
+    registerWatchdogHandler(ipcMain, {
+        isAuthorized: (event) => isAuthorizedWatchdogEvent(event, mainWindow, (url) => url === mainFrame.url),
+        httpClient
+    });
+
+    assert.equal(registeredChannel, WATCHDOG_CHANNEL);
+    const otherRenderer = { sender: { mainFrame }, senderFrame: mainFrame };
+    await assert.rejects(handler(otherRenderer, { healthy: true }), /not authorized/);
+    assert.equal(calls.length, 0);
+});
+
+test('rejects subframes and renderers on disallowed URLs', () => {
+    const mainFrame = { url: 'https://allowed.example/' };
+    const mainWindow = { isDestroyed: () => false, webContents: { mainFrame } };
+    const isUrlAllowed = (url) => url === mainFrame.url;
+    const blockedFrame = { url: 'https://blocked.example/' };
+    const blockedWindow = { isDestroyed: () => false, webContents: { mainFrame: blockedFrame } };
+
+    assert.equal(isAuthorizedWatchdogEvent({
+        sender: mainWindow.webContents,
+        senderFrame: { url: mainFrame.url }
+    }, mainWindow, isUrlAllowed), false);
+    assert.equal(isAuthorizedWatchdogEvent({
+        sender: blockedWindow.webContents,
+        senderFrame: blockedFrame
+    }, blockedWindow, isUrlAllowed), false);
+});
\ No newline at end of file